# How do colorblind people know colors? And what's up with purple?
**URL:** https://boards.straightdope.com/t/how-do-colorblind-people-know-colors-and-whats-up-with-purple/790225
**Category:** Factual Questions
**Created:** [June 30, 2017, 7:29pm UTC](https://boards.straightdope.com/t/how-do-colorblind-people-know-colors-and-whats-up-with-purple/790225 "2017-06-30T19:29:22Z")
**Posts on this page:** 4
**Page:** 2
### Author:  [@Nava](https://boards.straightdope.com/u/Nava)
#### Post date: [July 2, 2017, 4:49am UTC](https://boards.straightdope.com/t/how-do-colorblind-people-know-colors-and-whats-up-with-purple/790225/21 "2017-07-02T04:49:32Z")
One of my classmates discovered he couldn’t tell shades of orange the first time he helped his family pick the peaches by hand. He solved it by studying Civil Engineering, his brother inherited the farm.
Argentinian artist [Ciruelo Cabral](http://www.dac-editions.com/xindex.htm) is red-green blind. His wife classifies for him those shades he can’t tell apart and he’s simply very careful to always put a pencil back in the same place he took it from. When he needs to know what color something is, he asks.
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### Author:  [@Nava](https://boards.straightdope.com/u/Nava)
#### Post date: [July 2, 2017, 4:58am UTC](https://boards.straightdope.com/t/how-do-colorblind-people-know-colors-and-whats-up-with-purple/790225/22 "2017-07-02T04:58:34Z")
> [@BigT](#):
>
> Purple is made up of red and blue, and the red part is lower.
The last bit depends on what one is calling “purple”. The bluish shades, such as dark bruises, which often get called “purple” in English wouldn’t be called _púrpura_ in Spanish (they’re _morado_; our _púrpura_ is reserved to the color of Roman senatorial dye, which is considered a specific shade of _granate_), but English also refers to reddish shades such as that one or the color of pomegranate seeds as “purple”… and in those, the red is stronger.
Curiously enough, _royal purple_ and _púrpura real_ show me different shades :smack: I can even tell you which of the shades shown in the Spanish correspond to translations from English, as the English version shows more or less the same shade but the Spanish shows two very different ones. Reddish ones are “in Spanish in the original”; the bluish ones, likely to be translations from English.
In this portrait, Carlos III is wearing a [púrpura](http://www.abc.es/cultura/arte/abci-carlos-y-esplendor-artes-monarquia-201612060146_noticia.html) cloak. It’s a redder color than the royal purple I get from Unca Google.
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### Author:  [@nate](https://boards.straightdope.com/u/nate)
#### Post date: [July 2, 2017, 6:49pm UTC](https://boards.straightdope.com/t/how-do-colorblind-people-know-colors-and-whats-up-with-purple/790225/23 "2017-07-02T18:49:31Z")
I’m colorblind, there are a lot of shades of green and brown where if you asked me what color it was it would be a 50/50 guess for me. Same with some shades of red and green and some shades of blue and purple. The red/green LEDs that some products have to indicate off/on look the exact same to me so are pretty much useless as an indicator. I really wish they would use blue and red instead.
Thinking about this, I wonder if I can get my work to pay for enChroma glasses for safety’s sake (if they help with red/green identification). I work developing electrical measurement systems and always have to ask co-workers about the color of certain wires and have mistaken green for red more times than I can count.
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### Author:  [@BigT](https://boards.straightdope.com/u/BigT)
#### Post date: [July 3, 2017, 1:09am UTC](https://boards.straightdope.com/t/how-do-colorblind-people-know-colors-and-whats-up-with-purple/790225/24 "2017-07-03T01:09:34Z")
You guys are right. In my case, I was distinguishing between magenta or red-purples and purple. Magenta is equal parts blue and red, so anything bluer than it is gonna have less red than blue.
To me, purple in these types of discussions of hue describes the same perceptual color as violet. Not red-violet or blue-violet.
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